The invention relates to a display device that can alert vehicle drivers to the presence of a road shoulder, crosswalk, road boundary, traffic signs, and other traffic safety assistants, particularly under conditions such as heavy rain, fog, snow, or nighttime darkness that typically impair driver visibility.
For example, in the event of a thick fog, the driver may be unable to see a road shoulder or centerline. Similar problems with visibility are encountered in heavy rain or snow.
A typical solution to such problems is to separate the sidewalk from the roadway by slightly raising the sidewalk from the level of the roadway and to install a guard rail at the boundary to protect pedestrians.
In efforts to curb the recent increase in such traffic, accidents, a reflector plate, for example, is installed at the turning point of the road to reflect light incident thereon at a specific angle and to alert drivers and pedestrians to the need for added caution to ensure traffic safety. In places where the sidewalk is not separated from the roadway, a visible sign called the arrow mark is installed above the road, one of many steps taken to increase traffic safety.
However, such reflectors cannot reflect sufficient light to be easily spotted by drivers or pedestrians during nighttime hours or during rain, times when traffic safety is especially important. In addition, such reflectors can be buried in snow and rendered invisible. Steps between the roadway and sidewalk, and even the guard rails themselves, are often hard to spot during thick fog or heavy rain.
One aspect of the present invention is to provide a display device capable of indicating to car drivers the presence and position of the centerline, road shoulder, crosswalk, and other traffic signs, even in rain, thick fog, or heavy snow.
The present invention is a display device using columnar light, comprising a high-intensity discharge lamp equipped with a stabilizer, a reflector mirror coated with a heat-absorption film, a shutter, and a light-gathering lens; and a pole holding the high-intensity discharge lamp at a desired height above the road or its vicinity, wherein the shutter is placed at the primary focal point of the high-intensity discharge lamp, and the light choked by the shutter is gathered by the lens to illuminate the road or its vicinity. The shutter is placed at the primary focal point of the high-intensity discharge lamp, and the lens gathers the light choked by the shutter to illuminate the road or its vicinity.
In the invention, the above poles, each capable of emitting light from a high-intensity discharge lamp onto target spots, are installed on road shoulders, at boundaries between sidewalks and roadways, at crosswalks, at railroad crossings, and at sharp turns on mountain roads, where special attention to traffic safety is required. The light signs highlight areas that must remain visible to drivers. The invention employs a high-intensity discharge lamp, called an HID. HID lamps were developed to overcome conventional problems with light-emitting diodes and common laser lights, the light produced by which is weaker than headlights and is thus often obscured or drowned out in times of low visibility. Following intensive research and development efforts, a high-intensity discharge lamp has been developed that can emit light of an intensity greater than headlights.
Specifically, the illumination intensity of most vehicle headlights is 40,000 candela (cd) during normal conditions, while that of the center of the developed high-intensity discharge lamp reaches 50,000-1,000,000 candela (cd). This is one of the features of the present invention. Such high illumination intensity is provided by employing a high-intensity discharge lamp in combination with a reflector mirror coated with heat-absorption film, a shutter installed at the primary focal point of the lamp, and a lens that concentrates the light choked and amplified by the shutter.
The high-intensity discharge lamp can function at a voltage of 100 or 200V. As another feature of the invention, the lamp is equipped with: a sensor sensitive to light intensity or weather conditions, with an on/off switch operated manually or by the sensor. The lamp is capable of being set to switch off during times when there is no need for illumination.
When the present invention is employed as a safety sign in a crosswalk, high-intensity light beams are emitted across the road along both sides of the crosswalk. Thus, even when the crosswalk is not clearly visible, because covered by snow or for any other reason, such light beams or other signs remain visible above the crosswalk, indicating the presence and position of the crosswalk to drivers and pedestrians.
Particularly in the case of snow or dense fog, the light from the high-intensity discharge lamp is randomly reflected by snow flakes or raindrops above the road, forming a light plane. This significantly enhances visibility. In addition, the lighting thus produced is remarkably pleasing to the eye.